Generally, a vacuum cleaner draws in contaminants from a cleaning surface using a suction force of a vacuum source in a cleaner body and collects the drawn-in contaminants in the body. The vacuum cleaner includes the cleaner body, a suction nozzle facing the cleaning surface to draw in contaminants, and an extension pipe and a flexible hose to guide the contaminants drawn in via the suction nozzle into the cleaner body.
The suction nozzle includes, substantially at a central portion thereof, a suction port that receives a suction force to draw in contaminants. Accordingly, the suction force is strong at the central portion having the suction port whereas the suction force is weaker further from the central portion. Accordingly, the central portion which has the suction port can easily draw in contaminants so as to increase cleaning efficiency; however, side portions remote from the central portion have a decreased cleaning efficiency.
To solve that problem, a guide passage formed at the side portions of the suction port is often used to transmit the suction force through the suction port to the side portions of the suction port. Air drawn in via the side portions of the guide passage is collected all at once, thereby increasing flow speed. Because of turbulence caused by air streams colliding against each other, undesirable noise is generated.
JP Publication H1-1223918 discloses a suction nozzle having a protruding piece substantially at a center of one side of the suction port that serves as a partition. The protruding piece can prevent air streams drawn in via the suction port from directly colliding with each other and generating, thereby reducing noise resulting from the turbulence. Although air stream drawn in from the side portions along the guide passage do not directly collide with each other by the protruding piece; the air still makes noise when colliding with each side surface of the protruding piece.
Additionally, because the suction force exerts on both side portions of the suction port based on the protruding piece, alien materials, such as hairs, are held by a lower end of the protruding piece, thereby decreasing the suction force.